This invention relates to cartridges (also called containers) for storing dry analytical film chips which are small pieces of dry analytical film cut into a specific form, such as square, rectangle, circle or ellipsoid. The dry analytical film has a reagent layer wherein chemical reaction, biochemical reaction or immunological reaction occurs with a predetermined biochemical substance (hereinafter referred to as analyte) contained in a sample solution, such as blood or urine to produce an optical density change.
In general, to analyze qualitatively or quantitatively a specific component or an activity of a specific component in a sample solution is conducted in various industrial fields. Particularly, it is very important to analyze quantitatively the content or activity of a biochemical component or the content of a solid component of a body fluid, such as blood or urine, of an organism.
Recently, various dry integral multilayer analytical films (also called multilayer analytical element) have been developed which can determine the content or activity of a specific chemical component or the content of a specific solid component by merely spotting a small drop of a sample solution (U.S. Pat. Nos. 3,992,158, 4,292,272, etc.), and put to practical use. Filter paper-type test pieces and modifications thereof composed of single layer or multilayer were also proposed (U.S. Pat. No. 4,477,575), and are, in part, put to practical use. Since a sample solution can be analyzed simply and rapidly by using the dry analytical films compared with conventional wet analysis, to use the dry analytical films is particularly desirable for a medical organization or laboratory where a great number of sample solutions is analyzed.
As a method of analyzing a chemical component of a sample solution quantitatively by using the dry analytical film, the sample solution was spotted onto the dry analytical film (when there is a spreading layer, onto the spreading layer, on the other hand, when there is no spreading layer, onto the reagent layer directly), and is kept at a fixed temperature (incubated) for a predetermined period in an incubator (thermostatic oven) to induce a coloring reaction (dye-forming reaction). Subsequently, light for measurement containing a wavelength, which has been previously selected by the combination of a predetermined biochemical substance in a sample solution and a reagent contained in a dry analytical film, is irradiated to the dry analytical film, is irradiated to the dry analytical film, and the optical density is measured. The concentration or activity of the biochemical substance in the sample solution is determined by applying the optical density to a calibration curve indicating the correlation between the optical density and the concentration or activity of the biochemical substance which has been previously determined.
The above dry analytical film is composed of at least one layer of a reagent layer provided on a support formed of organic polymer, preferably further a spreading layer provided on the upper side of the reagent layer. The dry analytical film is formed into a chip, and put in a slide frame made of organic polymer (called chemical analytical slide) in order to treat by automatic operation. The slide frame also functions to keep the dry analytical film flat which tends to warp in dry conditions.
Incidentally, reagents in the reagent layer do not react, unless moisture is present. However, there is a possibility to start reaction at the moment to absorb moisture. Accordingly, the reagent layer must be kept in dry conditions until measurement is conducted. However, as mentioned above, the dry analytical film chip warps in dry conditions, and then, the dry analytical film chip is forced to be flat by placing in the slide frame. Moreover, although a part of the dry analytical film mounted in a slide frame is exposed at the opening of the upper slide frame to which a liquid sample is spotted, the exposed part (the upper surface of the spreading layer or reagent layer) of the dry analytical film is present at the bottom of an indentation formed by the thickness (in general, about 200 .mu.m to 1 mm) of the opening part of the upper slide frame. By the indentation structure, the upper surface of the dry analytical film mounted in the slide frame onto which a liquid sample is spotted is protected from damage and contamination.
As a cartridge for storing chemical analytical slides formed of a dry analytical film and a slide frame and protecting from moisture, Japanese Patent KOKAI Nos. 60-55263 and 60-55264 disclose a cartridge which is provided with an opening for ejecting the slides on one wall contacting an end panel of the cartridge and a flexible cover capable of closing the opening provisionally on the front of the opening parallel to the wall. As mentioned previously, the dry analytical film is necessary to be protected from moisture so as not to absorb moisture prior to use, and the flexible cover covers entirely the opening for ejecting the analytical slide because the main function of the cartridge is to protect the dry analytical films placed therein from moisture. Accordingly, the whole upper surface of the analytical slide is rubbed by the lower end of the flexible cover urged downwardly by the elasticity of the cover at the time of ejecting from the inside of the cartridge. The chemical analytical slide wherein the dry analytical film is placed in the slide frame is not damaged nor contaminated through rubbing by the cover, even in the case of the cover having the above structure.
However, analyzers using the above chemical analytical slides tend to be a big apparatus. That is, in a big medical organization, since a great quantity of chemical analytical slides is expended in a short period, a large size cartridge is used. Moreover, it is necessary to provide the number of cartridges corresponding to the number of the biochemical substances to be analyzed (analyte), and thereby, the space for setting the cartridge becomes great.
Besides, the cost of the slide frame is great to elevate the cost of chemical analytical slide, and the presence of the slide frame itself increases the size of cartridges and incubator.
Thereupon, the inventors developed several kinds of cartridges and incubator wherein dry analytical film chips can be used as it is (without mounted in a slide frame), and thereby, the cartridges can be made compact (Japanese Patent Application Nos. 4-5508, 4-16098).
In the cartridges, dry analytical film chips are stacked in the state that the support portion is positioned on the upper side, and each analytical film chip is taken out of the cartridge by sucking the support portion by a suction pad. Thereafter, the suction by the suction pad is changed over to the spreading layer or reagent layer portion, the film chip is turned, and conveyed to the incubator in the state that the spreading layer or reagent layer is positioned on the upper side. As a result, the conveying mechanism from the cartridge to the incubator is complex. Moreover, since the spreading layer and the reagent layer cannot be strongly sucked by the suction pad, troubles occurred due to the insufficient suction force, and carry-over by the suction pad sucking the spreading layer or reagent layer also occurred.